Method of jet deflection and apparatus therefor



M. KA'DOSCH Dec. 23, 1958 METHOD OF JET DEFLECTION AND APPARATUSTHEREFOR Filed July 23, 1956 INVE NTOR Mmaceu. KADoscH MMMPWW ATTOR NEYsUnited States Fatent METHOD or. JET DEFLECTION AND APPARATUS THEREFORMarcel Kadosch, Paris, France, assignor td Siiciete Nationale dEtudes etde Construction de Moteurs dAviation, Paris, France, a French companyApplication July 23, 1956, Serial No. 599,593

Claims priority, application France August 12, 1955 Claims. (Cl.60-3554) The present invention relates to arrangements for deflectingjets, and especially jets produced by reactionpropulsion devices. It ismore particularly concerned with a thermal method of causing thedeflection of a jet at the outlet of a discharge nozzle.

In accordance with the invention, the deflection of the jet is initiatedby creating in the flow of gas on the upstream side of the outletorifice of the discharge nozzle, an asymmetry in the transversedistribution of pressures by heating the part of the jet located at theside towards which the deflection is required, the opposite part of thisjet remaining at a lower temperature. There are thus obtained twoparallel streams of different temperatures in the jet.

The deflection thus started is strengthened and stabilised by adequatemeans for guiding the jet laterally, such as a convex edge or a grid ofdeflecting blades.

The present invention has a particularly advantageous application in thecase of reaction propulsion devices provided with an after-burningsystem. There can then be created a transverse gradient of temperatureseither by supplying only the fuel injectors situated on the side towardswhich deflection is desired, or by increasing the supply of fuel tothese injectors, and/or by reducing the supply of fuel to the injectorslocated on the side opposite to that at which deflection is to beproduced.

Thus, in the case in which retractable flame-holders are used, forexample holders of the fluid-screen type, it is possible to put out ofuse the flame holders in that part of the jet opposite to the sidetowards which deflection is desired, thus rendering the combustionincomplete in this portion.

Instead of effecting an internal combustion for the asymmetric heatingof the jet, it is clearly possible to heat one wall on the side towardswhich deflection is to be effected, for example, by means of an externalsource of heat.

The description which follows below with reference to the attacheddrawings (which are given by way of example only and not in any sense byway of limitation) will make it quite clear how the invention may becarried into effect.

Fig.1 is an axial diagrammatic cross-section of the rear part of areaction unit provided with a post-combustion device. 7

Fig. 2 is a cross-section along the line II-II of Fig. 1.

There can be seen on the drawings, the casing 1 of a turbo-jet unit, theexhaust cone of which is shown at 2. This propulsion unit comprises anafter-burning chamber *3 which terminates in an exhaust nozzle 4, thecrosssection of which can be varied, in known manner, for example bymeans of pivotally-mounted flaps 5.

The outlet orifice of the exhaust nozzle is extended by :a convexdeflecting edge 6 of circular shape, the front portion 6a of which formsan ejector, drawing-in the ambient air under the effect of the flow ofgas passing out of the discharge nozzle 4. A grid of annular deicefleeting blade 7 is fixed at the rear of the deflecting edge 6.

The after-burning device comprises two oppositelyarranged groups ofinjectors 8, 9, connected to sepai ate manifolds 10, 11, which aresupplied with fuel through valves 12, 13, enabling the rate of flow tobe regulated. Flame holders 14,-of annular shape, are provided in thecentre of the jet, close to the forward portion of the postcombustionchamber 3.

In order to obtain a deflection of the jet, one of the groups ofinjectors 8, 9 is fed with fuel, say the group 8; the valve 12 isopened, the valve 13 remaining closed. The introduction of fuel throughthe off-centered injectors 8 produces an asymmetric heating of the flow,and by this means a transverse gradient of temperature is created whichhas the effect of deflecting the jet towards the hotter side, i. e.towards the side adjacent the injectors 8. i The jet therefore is urgedto flow along the path illustrated by the arrows and is thus appliedagainst the adjacent part of the deflecting edge 6 and engages theadjacent part of the grid of blades 7.

The deflection of the jet thus produced gives rise to a transversethrust which creates a moment which can be employed for steering inaircraft.

In order to obtain a deflection in the opposite direction, the procedureis reversed: the valve 13 is opened instead of the valve 12. Thedirectional effect produced is opposite to that obtained in thepreceding case.

It will be understood that it is possible to obtain a deflection of thejet in a plane at right angles to that of Fig. 1 (that is to say towardsthe left-hand or the righthand side of Fig. 2) by arranging two othergroups of injectors displaced by with respect to those which are shownin the drawings. The groups of injectors could also be distributed overquarters of the circumference, for example by dividing the manifolds 10and 11 into two halves and using separates valves for each of thesehalves.

In the case in which the after-burning device is in operation at themoment when it is desired to deflect the jet, that is to say if all theinjectors are simultaneously and uniformly supplied with fuel, theoperation is carried out in the following manner.

The supply of fuel to the injectors located at the side towards whichdeflection is desired to be made is increased, or the supply is reducedto the injectors located in the opposite side or again, these twooperations are preferably carried out simultaneously, by providing asuitable valve system for that purpose.

What I claim is:

1. In a jet propulsion unit having a propulsive nozzle and a tail pipefor leading a continuous stream of motive gas thereto, a jet deflectingdevice comprising jet guiding means positioned downstream of said nozzleand extending outside and laterally of the normal undeflected path ofthe jet, and controllable means in said tail pipe which increases thetemperature of an eccentric portion of said stream relatively to theremainder thereof whereby said stream is dissymmetrically heated and atransverse temperature gradient is established thereacross.

2. Jet deflecting device as claimed in claim 1, wherein the controllablemeans comprise means which effects a dissymmetrical combustion withinthe stream.

3. Jet deflecting device as claimed in claim 2, wherein the controllablemeans comprise means which effects a dissymmetrical injection of fuelinto the stream.

4. Jet deflecting device as claimed in claim 3, wherein the fuelinjecting means comprise a plurality of fuel injectors distributedsymmetrically in the tail pipe, separate fuel supply lines which feed atleast two groups of said References Cited in the file of this patentUNITED STATES PATENTS Forsyth Sept. 23,1947 10 4 FOREIGN PATENTS 161,402Australia Feb. 22, 1955 1,057,271 France Oct. 28, 1953 OTHER REFERENCESPublication: Chandler-Aero Digest Magazine, vol. 60, No. 4, pages100-102, April 1950.

